A digital signature (ID). like a conventional handwritten signature, identifies the person signing a document. Unlike a handwritten signature, a digital signature is difficult to forge because it contains encrypted information that is unique to the signer and easily verified. It is usually password protected and can be stored on your computer in PKCS #12 file format (Personal Information Exchange File, PFX).

When you buy a new digital signature, you get .spc file that contains the certificate and .pvk file that contains your private keys. U se Microsoft command-line tool Pvk2Pfx to convert them into a PFX file. See detail here.

The following command generates the .pfx file Mypfxfile.pfx from Mypvkfile.pvk and Myspcfile.spc. The command supplies the password mypassword for the .pvk file, which becomes the password for the .pfx file Mypfxfile.pfx: